Electronic equipment must often function in the presence of high frequency disturbances. These disturbances normally are generated by external sources, but sometimes can be generated by the electronic equipment itself. These disturbances or high frequency interferences are often referred to as electromagnetic interference (hereinafter "EMI"). EMI can cause tremendous problems with sensitive electronic circuits, especially those found in communication devices (e.g. two-way radios). It is also common for interference to be referred to as radio frequency interference (hereinafter "RFI") when speaking about radio communication equipment.
Methods of reducing EMI/RFI interference include the use of shielded housings and cables, EMI filters, ferrite beads, and EMI suppressant tubing. Each of these methods has its advantages and disadvantages in terms of both cose, and ease of implementation. For example, ferrite beads are very useful in electronic applications in attenuating EMI from cables carrying electrical signals. Unfortunately, ferrites have the disadvantages of being rigid and normally require large amounts of space to implement. In comparison, conventional EMI suppressant tubing provides a simple, low cost, means of suppressing undesired EMI in electrical cables. Since EMI suppressant tubing is flexible, it can be slipped over standard cables, and can suppress both conducted and radiated electromagnetic interference.
A need arises in the field of radio communications for cable assemblies having EMI suppressant capabilities. For example, in normal communication applications, users will normally use devices such as remove speaker/microphones which are attached to two-way radios. Since the radio antenna is normally emitting strong electromagnetic fields, there is a strong tendency for electromagnetic energy to be coupled back into the radio via the remote speaker/microphone cable. This interference causes serious problems for the sensitve electronic circuits in the radio. The electromagnetic interference causes such problems as audio and radio frequency "densense " which tends to render radios inoperable.
A cable assembly which can suppress electromagnetic interference and would take up minimal space would be very beneficial.